White phosphorus $P_{4}$ has the following characteristics:

Which element of group $15$ forms the most basic compound with hydrogen?

Cyclic polymetaphosphates have the general formula $(PO_3)_n^{n-}$. Which of the following statements is true for the cyclic trimeric metaphosphate?

In the brown ring test,the brown colour of the ring is due to

On reaction with $Cl_2$,phosphorus forms two types of halides $A$ and $B$. Halide $A$ is a yellowish-white powder,while halide $B$ is a colourless oily liquid. Identify $A$ and $B$ and write the formulas of their hydrolysis products.

Pure $HNO_3$ is a colorless liquid,but it turns light brown in the presence of light. This is due to its decomposition into which of the following substances in small amounts?